Songbird vocal learning provides an excellent model system in which to study the relationship of brain and behavior. Electrophysiological data from freely behaving birds suggest that behavioral state is relevant to song maintenance. Auditory feedback, which is necessary for the maintenance of song, is differentially regulated in two functionally and anatomically distinct pathways of the forebrain song system according to behavioral state. Our proposal aims to combine in vivo and in vitro electrophysiological techniques to examine the specific effects of cholinergic input on the transmission of auditory feedback in a forebrain nucleus which is a nexus of auditory and premotor activity. Cholinergic systems have been shown to be related to attention, arousal, and memory in a number of organisms, including humans. This series of experiments will therefore have the potential to illuminate the role of feedback and attentional mechanisms in the performance of complex motor behaviors.